Generally, washing machines are classified into a pulsator-type washing machine having a vertically-provided drum and a drum-type washing machine having a horizontally-provided drum.
In the drum-type washing machine, since the drum is disposed in a horizontal direction as described above, a washing operation is performed by dropping laundry loaded in the drum.
FIGS. 1 and 2 schematically show a conventional structure of the above-mentioned drum-type washing machine.
That is, the drum-type washing machine is configured to include a main body 10, a tub 20 mounted in the main body 10, a drum 30 rotatably mounted in the tub 20 and a driving unit for driving the drum 30.
In this case, a loading opening 11 for loading the laundry is disposed on a front surface of the main body 10. A door 40 for opening and closing the loading opening is mounted at a peripheral portion of the loading opening 11.
Further, a gasket 50 for sealing between the door 40 and the loading opening 11 is mounted at an inner periphery of the loading opening 11.
Further, dampers 21 are disposed at opposite sides below an outer surface of the tub 20 such that the tub 20 is supported in the main body 10.
In this case, a heater 60 for washing water which heats the washing water is disposed in a lower space inside the tub 20.
Further, the driving unit is configured to include a driving motor 71 for driving the drum 30 and a belt 72 connected to transfer a driving force of the driving motor 71 to the drum 30. Recently, a direct connection type drum washing machine in which a configuration of the belt 72 is omitted and the driving motor 71 is directly mounted on the tub has been provided.
However, in the above-mentioned conventional washing machine, even when a washing operation for a small amount of laundry or a washing operation for slightly contaminated laundry is performed, a large amount of water is unnecessarily consumed and the washing operation is performed for an approximately same period of time as a general washing process, thereby having a problem such as a unnecessary large consumption of electricity.
Particularly, although it is efficient for a washing performance to perform a steeping process before a washing operation, since a consumption amount of the washing water for the steeping process is considerably large, the steeping process is omitted in a general washing process. Accordingly, the highest washing performance cannot be obtained. Further, a process for sterilizing the laundry is not separately performed in a conventional washing process.
Although not shown in the drawings, recently, there is a structure in which a heater for washing water, which heats washing water, is separately disposed in the washing machine to enable a boiling washing operation. However, since sterilization of the laundry is performed simply by a boiling operation, it is not preferable due to an increase in washing water and power consumption amount required for the boiling operation. Thus, a new operation capable of sterilizing the laundry with a small amount of washing water and low power consumption is required.
Further, the conventional washing machine has a problem of causing a secondary contamination through the washing process since the contaminants are not removed at an initial step in case of baby clothes having a lot of contaminants. For example, the baby clothes are contaminated with contaminants such as milk, mother's milk, spit, vomit, baby food, cake, and feces differently from general laundry. Since a portion of the contaminants has a relatively large size, it is dissolved in the washing process, thereby causing the secondary contamination.
Therefore, a method of efficiently washing laundry having lots of contaminants such as baby clothes has been studied. Further, particularly, the baby clothes may be frequently contaminated with contaminants having protein components. Accordingly, a method of efficiently removing the contaminants having protein components has been studied. In case of baby clothes, necessity for sterilizing the laundry or removing ticks is higher compared to general laundry.